As computing technology has advanced, computing devices have become increasingly commonplace in our lives. Situations oftentimes arise in which people desire to keep some information on or available to their computing devices private, such as pictures or documents stored on their devices, communications with other computing devices or services, and so forth. Unfortunately, computing devices can be susceptible to attack from malicious users, malicious programs, and so forth, and if such an attack is successful information that a user desires to keep private can be revealed to others. Maintaining usability of computing devices in a wide range of environments and situations, while still protecting such computing devices from such attacks, remains difficult.